Postpublished at 20:46 Greenwich Mean Time 18 February 2018
Real Madrid are actually closer in the league to another Barcelona side - 16th-placed Espanyol.
Asensio scores twice in topsy-turvy game
Marcelo comes off injured for Madrid
Zidane's side beat PSG 3-1 on Tuesday in Champions League
Get involved - #bbceurofooty
Emlyn Begley
Real Madrid are actually closer in the league to another Barcelona side - 16th-placed Espanyol.
Has there ever been a worst title defence from an elite side?
Twenty points behind Barcelona if they lose today, with one game in hand they're far from guaranteed to win.
Real Madrid's game in hand - at Leganes - is on Wednesday, at 17:45 GMT.
That will end just before that night's Champions League games are starting.
Real Betis 2-1 Real Madrid
We could see a landmark day today.
Real Madrid have not lost any of their 28 La Liga games with Lucas Vazquez starting - 26 wins and two draws.
Real Betis 2-1 Real Madrid
Wow. Real Betis lead at half-time and they deserve it. They've been fantastic.
But it's more La Liga woe for Real Madrid.
Real Betis 2-1 Real Madrid
A rare bit of first-half injury time added on in La Liga, one minute.
Real Betis 2-1 Real Madrid
Real Betis 2-1 Real Madrid
Real Betis' on-loan right-back Antonio Barragan hacks down Marco Asensio, yellow card.
Real Betis 2-1 Real Madrid
As things stand, Real Madrid are only three points above fifth-placed Sevilla (albeit with a game in hand).
Keep on like this and winning the Champions League might be their best bet for qualifying next season.
Real Betis 2-1 Real Madrid
Good footwork from Cristiano Ronaldo to lose two defenders at the edge of the box, but then hits the ball at Antonio Adan from a tight angle.
What has happened to Madrid in the league this season?
#bbceurofooty
Zaffran Khan: What a legend Joaquin is for Betis would love to have seen him in the Premiership at his peak
He'd still get in most teams now, based on this performance
Nacho own goal
Real Madrid's La Liga nightmare continues. The ball comes to Real Betis left-back Junior in the box, he's in space, and shoots. Keylor Navas saves it but it squirms past him, and it hits the shins of Nacho and goes into his own net.
Real Betis 1-1 Real Madrid
Cristiano Ronaldo has the ball in the back of the net, but he was offside from Casemiro's through ball as Betis tried to play the ball out of defence.
Real Betis 1-1 Real Madrid
Real Madrid now put in a good cross, it's Marco Asensio from a corner, but Cristiano Ronaldo heads straight at the keeper.
Real Betis 1-1 Real Madrid
Aissa Mandi
It's been coming. Joaquin puts in another excellent cross, Betis defender Aissa Mandi climbs over his markers and powers a header past Keylor Navas.
Real Betis 0-1 Real Madrid
Real Betis winger Joaquin - who is not playing like a 36-year-old - runs Nacho ragged and wins a free-kick.
Real Betis 0-1 Real Madrid
Marcelo can't play on and he's replaced by Theo Hernandez, a summer signing from Atletico Madrid.
He's got two and a half weeks to recover for the Paris St-Germain second leg.
Real Betis 0-1 Real Madrid
Real Madrid left-back Marcelo pulls up with a hamstring injury. He wasn't near an opposition player so I presume it's genuine. He tries to play on but he's hobbling.
Real Betis 0-1 Real Madrid
WOOOF. Real Betis have a free-kick, 30 yards out, and Joaquin sends an absolute rocket towards the top corner which a diving Keylor Navas does well to touch around the post. Marvellous hit.